Computer algebra system

Giac/Xcas is a free computer algebra system for Windows, Mac OS X and
Linux/Unix (license GPL3). It has
a compatibility mode for maple, mupad and the TI89.
It is available as a standalone program (graphic or text interfaces)
or as a C++ library.
It's name is derived from GiNaC
and means Giac Is A Computer algebra system.

The source code of my contribution to the HP49G CAS
is released under the
LGPL
license of the Free Software Foundation. If you want to modify the
CAS on your calculator, please get the file
casrelease.zip, unzip it, and follow the instructions in the file
CASrelease/README. Warning, the file casrelease.zip
is not released under the LGPL license and may not be redistributed as is.
The files subject to the LGPL license are all the files contained in the
CASrelease/ROM/CAS and CASrelease/ROM/CAS2 directories
except files containing ALG48 code, namely
CAS/berle.s*, CAS/binary.s*, CAS/distdiv.s*, CAS/error.s*, CAS/errors.s*,
CAS/grobner.s*, CAS/mkpoly.s*, CAS/pfctr.s*, CAS/prime.s*, CAS/qarth.s*,
CAS/root.s*, CAS/smod.s*, CAS/util.s*, CAS/zckconv.s*, CAS/zcmp.s*, CAS/znext.s*,
CAS/zpush.s*, CAS/zsutil.s*, CAS/ztests.s*, CAS2/asmgamma.s*, CAS2/asmpsi.s*,
CAS2/numgamma.s*, CAS2/numpsi.s*, CAS2/qpi.s*, CAS2/symgamma.s*, CAS2/sympsi.s*,
CAS2/util.s*, CAS2/zfact.s*